In one technology described in JP Utility Model Publication Number H1-161825, a depression force applied to an accelerator pedal is detected and, when the depression force average value becomes a predetermined value or greater within a given period, an erroneous operation is determined, thereby closing a throttle valve of an engine to activate the brake.
While an erroneous operation to depress an accelerator pedal instead of a brake pedal may occur, for example, in a parking area or the like, the accelerator operation in this event tends to constantly change depending on a situation on the spot including various elements and thus is not unitary. Therefore, when a determination as to whether or not the operation is a erroneous operation is made solely based on an average value of pedal depression forces as in the conventional technique described in the JP Utility Model Publication Number H1-161825, there is a possibility that an accurate determination cannot be made.